Surround Sound (e.g., ATSC A/52 5.1) can only place sound at 5 places (5.1) (FIG. 1), place sound at 7 places (7.1), or place sound at on the line between those places (panning). 3D Sound (e.g., BACCH and other cross-talk cancellers) allows Binaural Audio with 2 Loudspeakers (B2L), such that two speakers can place a sound anywhere in 3D space. Accordingly, when using 3D Sound, the other 3/5 speakers in 5.1/7.1 are not needed to place a sound in 3D space.
However, a large number of console gamers have 5.1 surround sound setups. These gamers currently get more value out of 5 speakers than they do out of 2 speakers. These gamers would like to continue to use 5 speakers, and get more value out of 5 speakers than they do out of 2 speakers.
Accordingly, there is a need to accomplish the 3D effects of 3D Sound while shaking more than two speakers, and preferable all 5/7 speakers. Preferably, the shaking of all 5/7 speakers is accomplished in a manner that actually makes the 5/7 speaker solution sound better.
Listening to Binaural Audio from signals from cross-talk canceller inputted to two (XTC) Speakers in front of the listener (FIG. 2) is desirable. With Headphones, if HRTF mismatch between listener and recording occurs, the sound collapses to inside the listener's head. With BACCH-SP, and two XTC speakers in front of the listener (FIG. 2), if HRTF mismatch between listener and recording occurs, the sound collapses to the stereo pan (speaker locations). The sound is still outside the listener's head and in front of the listener, the correct position for on-screen action.
Listening to binaural Audio with two XTC Speakers behind the listener (FIG. 3) is also enjoyable (e.g., in an automobile, in a video gaming chair, and/or speakers in a room). Again, with Headphones, if HRTF mismatch between listener and recording occurs, the sound collapses to inside the listener's head. With BACCH-SP, and the XTC speakers behind the listener, if HRTF mismatch between listener and recording occurs, the sound collapses to the stereo pan (speaker locations). The pair of rear speakers can be crosstalk cancelled and used to create the sound behind the listener.
One of the reasons for imperfection in the perception of the placement of a sound in 3 d space when using 5.1 or 7.1 setup can be described by comparing a Typical set-up (typical) (FIG. 4) with the Coherent set-up (perfect) 5.1 (FIG. 5) are as follows:
Typical 5.1 (FIG. 4): The Left and Right speakers are the only speakers with full size, full power, and full range; other channels (speakers) are special satellites and should be used for special effects; the speakers are positioned at non-uniform distances, e.g. the speakers are arranged in a square; when multiple listeners are in the space, most of listeners are off-center; the Left-Right Speaker angle about +/−30 degrees; the distance from listener to speakers is undefined; and/or the distance from the microphone to the source might or might not meet P&E recommendations of 6.5-7.5 feet.
Coherent 5.1 (FIG. 5): Identical Speakers are used. Identical Amplification is used. Identical Response of speakers is accomplished. Uniform distances are implemented. The speakers are arranged in a circle. There is a single listener in the center. The Left-Right speaker angle is exactly +/−22.5 or +/−30 degrees. The distance from listener to speakers meets P&E recommendations of 6.5-7.5 feet. The distance from microphone to source meets P&E recommendations of 6.5-7.5 feet.
Even though experts argue that the assumption that sound is always superimposable is not true, relying on this assumption typically works.